1. Field of the Invention
The invention relates to a surface-discharge-scheme alternating-current-type plasma display panel, and more particularly, to configuration of a partition wall for partitioning a discharge space of the plasma display panel.
The present application claims priority from Japanese Application No. 2001-283224, the disclosures of which are incorporated herein by reference for all purposes.
2. Description of the Related Art
In recent times, a surface-discharge-scheme alternating-current-type plasma display panel becomes increasingly commonplace as a slim, large sized color screen display.
FIG. 7 to FIG. 11 illustrate a panel structure of a conventional surface-discharge-scheme alternating-current-type plasma display panel (hereinafter referred to as xe2x80x9cPDPxe2x80x9d). FIG. 7 is a schematic front view of the conventional PDP. FIG. 8 is a sectional view taken along the V1xe2x80x94V1 line of FIG. 7. FIG. 9 is a sectional view taken along the V2xe2x80x94V2 line of FIG. 7. FIG. 10 is a sectional view taken along the W1xe2x80x94W1 line of FIG. 7. FIG. 11 is a sectional view taken along the W2xe2x80x94W2 line of FIG. 7.
In FIGS. 7 to 11, a front glass substrate 10 serving as the display surface of the PDP has a back surface on which a plurality of row electrode pairs (X, Y) are arranged in parallel to each other in a column direction of the front glass substrate 10 (in the vertical direction in FIG. 7).
Each of the row electrodes X is constructed of transparent electrodes Xa each of which is formed of a T-shaped transparent conductive film made of ITO or the like, and a bus electrode Xb which is formed of a metal film having a double-layer structure made up of a black conductive layer and a main conductive layer. The bus electrode Xb extends in the row direction of the front glass substrate 10 and is connected to a base member, having a smaller width, of each of the transparent electrodes Xa.
Likewise, each of the row electrodes Y is constructed of transparent electrodes Ya each of which is formed of a T-shaped transparent conductive film made of ITO or the like, and a bus electrode Yb which is formed of a metal film having a double-layer structure made up of a black conductive layer and a main conductive layer. The bus electrode Yb extends in the row direction of the front glass substrate 10 and is connected to a base member, having a smaller width, of each of the transparent electrodes Ya.
The row electrodes X and Y are arranged in alternate positions in the column direction of the front glass substrate 10 (the vertical direction in FIG. 7). In each row electrode pair, each of the transparent electrodes Xa placed along the bus electrodes Xb extends toward the bus electrode Yb and each of the transparent electrodes Ya placed along the bus electrode Yb extends toward the bus electrode Xb, so that the tops of larger-width members of the respective transparent electrodes Xa and Ya are opposite to each other with a discharge gap g, having a predetermined width, in between.
A dielectric layer 11 is also formed on the back surface of the front glass substrate 10 so as to cover the row electrode pairs (X, Y). On the back surface of the dielectric layer 11, an additional dielectric layer 11A protrudes from the back surface of the dielectric layer 11 in a position opposite to the adjacent bus electrodes Xb and Yb of the respective row electrode pairs (X, Y) adjacent to each other and also opposite to a region between the adjacent bus electrodes Xb and Yb concerned. The additional dielectric layer 11A is formed so as to extend in parallel to the bus electrodes Xb, Yb.
A protective layer 12 made of MgO is formed on the back surfaces of the dielectric layer 11 and additional dielectric layers 11A.
The front glass substrate 10 is situated in parallel to a back glass substrate 13 having a surface facing toward the display surface on which column electrodes D are arranged parallel to each other at predetermined intervals and each extends in a direction at right angles to the row electrode pair (X, Y) (the column direction) in a position opposite to the paired transparent electrodes Xa and Ya in each of the row electrode pairs (X, Y).
On the surface of the back glass substrate 13 on the display surface side, a white dielectric layer 14 covers the column electrodes D, and partition walls 15 are formed on the dielectric layer 14.
Each of the partition walls 15 is shaped in a ladder pattern with vertical walls 15a each of which extends in the column direction in a position between two adjacent column electrodes D arranged in parallel, and transverse walls 15b each of which extends in the row direction in a position opposite to the additional dielectric layer 11A.
The ladder-shaped partition walls 15 are arranged in parallel to each other in the column direction such that an interstice SL is interposed between adjacent partition walls 15 in a position opposite to an area between the bus electrodes Xb and Yb of the row electrodes X and Y which are adjacent to each other in the column direction and positioned back to back.
Each of the ladder-shaped partition walls 15 partitions the discharge space, interposed between the front glass substrate 10 and the back glass substrate 13, into areas each opposite to the transparent electrodes Xa and Ya paired in each row electrode pair (X, Y), to define discharge cells C each formed in a quadrangular shape.
In each discharge cell C, a phosphor layer 16 is provided on a face of the dielectric layer 14 and the four side faces of the vertical walls 15a and transverse walls 15b of the partition wall 15 which face toward the discharge cell C so as to cover all the five faces. The phosphor layers 16 are arranged in order a red color (R), a green color (G) and a blue color (B) in the row direction for each discharge cell C.
The discharge space is filled with a discharge gas.
In FIGS. 7 to 11, reference numeral 17 represents a black light absorption layer (light shield layer) formed between the back-to-back bus electrodes Xb and Yb of the respective row electrodes X and Y adjacent to each other in the column direction, and reference numeral 18 represents a light absorption layer (light shield layer) formed in a position opposite to each vertical wall 15a of the partition wall 15.
The PDP displays images as follows: first, an addressing discharge is selectively caused between one of the row electrodes X, Y and the column electrode D in each discharge cells C. As a result, lighted cells and non-lighted cells are distributed over the panel surface in accordance with an image to be displayed.
Then, a discharge sustaining pulse is applied alternately to the row electrodes X and Y of each pair for a sustaining discharge. Ultraviolet rays generated through the sustaining discharge in each lighted cell excites the red (R), green (G) or blue (B) phosphor layer 16 in each lighted cell to allow the phosphor layer 16 to emit light.
In the panel structure of the conventional PDP as described above, a connection part between the bus electrode Xb, Yb and each of the base members of the transparent electrodes Xa, Ya of each of the row electrodes X and Y is situated in a position overlapping the connection part and the transverse wall 15b of the partition wall 15 when viewed from the display surface of the front glass substrate 10. For the reason of this positional relationship, the sustaining discharge produced between the transparent electrodes Xa and Ya in each of the row electrode pairs (X, Y) is impaired by the transverse wall 15b of the partition wall 15, to induce deterioration of its discharge properties, leading to a problem of adversely affecting the forming of images.
With increasingly higher definition of the PDP in recent times, the width between the transverse walls 15b of each partition wall 15 (width of the discharge cell C in the column direction) is increasingly smaller. For this reason, providing a sufficient width of the discharge cell C in the column direction makes it difficult to prevent the deterioration of the sustaining discharge properties.
The present invention has been made to solve the problems associated with conventional surface-discharge-scheme alternating-current-type plasma display panels as described above.
It is therefore an object of the present invention to provide a plasma display panel which is capable of preventing the properties of a sustaining discharge from being adversely affected by a partition wall provided for defining discharge cells in order to form an image with high definition.
To attain the above object, according to a first feature of the present invention, a plasma display panel including: a front substrate; a plurality of row electrode pairs arranged in a column direction on a back surface of the front substrate, and each extending in a row direction and forming a display line; a back substrate placed opposite the front substrate with a discharge space interposed; and a plurality of column electrodes arranged in the row direction on a surface of the back substrate facing toward the front substrate, and each extending in the column direction to intersect the row electrode pairs and form unit light-emitting areas in the discharge space at the respective intersections. The plasma display panel in the first feature comprises partition walls provided between the front substrate and the back substrate for defining each of the unit light-emitting areas, each of the partition walls comprising: vertical walls each positioned between adjacent unit light-emitting areas of the unit light-emitting areas in the row direction and extending in the column direction to form a partition between the adjacent unit light-emitting areas; and transverse walls bridging the vertical walls to define a top and bottom edge of the unit light-emitting areas, each transverse wall having an edge part, defining each of the unit light-emitting areas, having a central part located midway between adjacent vertical walls of the vertical walls protruding beyond a part coupled to the vertical wall toward the outside of the unit light-emitting area in the column direction.
With the plasma display panel according to the first feature, the partition walls having the vertical walls extending in the column direction and the transverse walls extending in the row direction partition the discharge space interposed between the front substrate and the back substrate into the unit light-emitting areas.
In between vertical walls of the partition wall arranged in the row direction, the transverse wall has the edge part defining the top or bottom edge of the unit light-emitting area. The edge part has the central part located midway between the vertical walls adjacent to each other, and the coupling part at which the transverse wall is coupled to the vertical wall. The central part protrudes beyond the coupling part toward the outside of the unit light-emitting area in the column direction. Accordingly, each of the unit light-emitting areas defined by the partition wall has a length in the column direction between the central parts of the transverse walls between the adjacent vertical walls longer than that between the coupling parts at which the transverse walls are coupled to the vertical wall.
As a result, the first feature allows the offset arrangement of the row electrode and the transverse wall of the partition wall, both of which extend in the row direction and are arranged approximately in the same position when viewed from the front substrate, in the mid-position between adjacent vertical walls to prevent the row electrode and the transverse wall from complete overlapping each other, when viewed from the front substrate.
For example, when each of the row electrodes comprises a bus electrode extending in the row direction and transparent electrodes each protruding in island-like form from the bus electrode in the column direction in each unit light-emitting area, it is possible to place the connecting part between the bus electrode and transparent electrode of the row electrode in a position in which the connecting part does not overlap the transverse wall of the partition wall when viewed from the front substrate.
Thus, the plasma display panel provided by the present invention is capable of preventing the sustaining discharge, caused between the row electrodes when an image is generated, from being impaired by the transverse wall of the partition wall to induce deterioration of its discharge properties to thereby adversely affect the forming of images, and further is capable of forming the images with high definition because the adequate discharge properties are provided.
To attain the aforementioned object, a plasma display panel has, in addition to the configuration of the first feature, a second feature in that the transverse wall is formed in a band shape protruding toward the outside of each of the unit light-emitting areas in the column direction and toward a central point midway between the adjacent vertical walls from a point coupled to one of the adjacent vertical walls.
With the plasma display panel according to the second feature, each of the partition walls is shaped in an approximate ladder shape with the vertical walls arranged at required intervals in the row direction and a pair of band-shaped transverse walls coupling the vertical walls, arranged in the row direction, at both ends of each of the vertical walls. Each of the pair of band-shaped transverse walls has a shape protruding the central part, located midway between adjacent vertical walls, beyond the part coupled to the vertical wall toward the outside of the unit light-emitting area in the column direction.
Due to this shape, the partition wall defines the unit light-emitting areas such that each of the unit light-emitting areas has a length in the column direction between the central parts of the transverse walls located midway between the adjacent vertical walls longer than that between the parts at which the transverse walls are coupled to the vertical wall.
To attain the aforementioned object, a plasma display panel has, in addition to the configuration of the second feature, a third feature in that the transverse wall extends linearly toward the central point midway between the adjacent vertical walls from the point coupled to the one of the adjacent vertical walls.
With the plasma display panel according to the third feature, the transverse wall of the approximately ladder-shaped partition wall has a V-letter or inverted-V-letter shape between adjacent vertical walls. Due to this shape, the partition wall defines the unit light-emitting areas such that each of the unit light-emitting areas has a length in the column direction between the central parts of the transverse walls midway between the adjacent vertical walls longer than that between the parts at which the transverse walls are coupled to the vertical wall.
To attain the aforementioned object, a plasma display panel has, in addition to the configuration of the second feature, a fourth feature in that the transverse wall extends in a curved line toward the central point midway between the adjacent vertical walls from the point coupled to the one of the adjacent vertical walls.
With the plasma display panel according to the fourth feature, the transverse wall of the approximately ladder-shaped partition wall is curved between adjacent vertical walls to protrude toward the outside of each unit light-emitting area in the column direction and toward the central part located midway between the adjacent vertical walls from the part coupled to the vertical wall. Due to this curved shape, the partition wall defines the unit light-emitting areas such that each of the unit light-emitting areas has a length in the column direction between the central parts of the transverse walls located midway between the adjacent vertical walls longer than that between the parts at which the transverse walls are coupled to the vertical wall.
To attain the aforementioned object, a plasma display panel has, in addition to the configuration of the fourth feature, a fifth feature in that the transverse wall is formed in an arc shape curving in a direction of the outside of the unit light-emitting area in the column direction, between the adjacent vertical walls.
With the plasma display panel according to the fifth feature, the transverse wall of the approximately ladder-shaped partition wall is formed in a shape of continuing the arc shapes each bridged between adjacent vertical walls such that a central part of each of the arcs protrudes toward the outside of each unit light-emitting area in the column direction. Due to this shape, the partition wall defines the unit light-emitting areas such that each of the unit light-emitting areas has a length in the column direction between the central parts of the transverse walls located midway between the adjacent vertical walls longer than that between the parts at which the transverse walls are coupled to the vertical wall.
To attain the aforementioned object, a plasma display panel has, in addition to the configuration of the first feature, a sixth feature in that each of the vertical walls of the partition wall in one row, arranged at required intervals in the row direction, is placed in a position shifted by a required length from a corresponding vertical wall of the vertical walls in another row adjacent to the one row in the column direction.
With the plasma display panel according to the sixth feature, the vertical walls of the partition wall in one row (or line) are offset in positions in the row direction with respect to the corresponding vertical walls in another row adjacent to the one row in the column direction so that the vertical walls of the partition walls are arranged in an approximately corrugated form in the column direction. Hence, when the central part of the transverse wall located midway between the adjacent vertical walls of the partition wall protrudes in a direction of another partition wall adjacent to the above partition wall in the column direction, the interference of the protruding parts of the opposite transverse wall of the adjacent partition walls is avoided.
Thus, the spacing between adjacent partition walls in the column direction is successfully decreased, resulting in improvement in high definition of the plasma display panel.
To attain the aforementioned object, a plasma display panel has, in addition to the configuration of the sixth feature, a seventh feature in that the adjacent vertical walls in two rows adjacent to each other in the column direction are shifted in the row direction by a length corresponding to half a length between the vertical walls adjacent to each other in the row direction in each row.
With the plasma display panel according to the seventh feature, the vertical wall of the partition wall in one row is placed in a position shifted in the row direction with respect to the corresponding vertical wall in another row adjacent to the one row in the column direction by a length corresponding to half the spacing between the vertical walls adjacent to each other in the row direction in each row, or equivalently, in a position shifted in the row direction by a one-half pitch of the unit light-emitting area, defined by the partition wall, in the row direction, so that the vertical walls are positioned zigzag in the column direction.
Thus, the spacing between adjacent partition walls in the column direction is successfully decreased as much as possible, resulting in improvement in high definition of the plasma display panel.
These and other objects and features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.